Introduction

The Mechanical Advantage of a Wheel/Axle is the ratio of input distance to output distance, or the ratio of the two diameters. A reliable value for MA is completely dependent on reliable measurements. This activity will train you to obtain reliable data and report it in a clear way.

Activity

Use the slideshow below to learn how to read a Vernier caliper.


The following data table provides a model for reporting your results.

Assessment

Skill Area O: Obtaining Data or Evidence

When students obtain data or evidence in a scientific investigation, they should expect to

• use a wide range of equipment and materials appropriately;
• manage their working environment to ensure the safety of themselves and others;
• make observations and measurements to a degree of precision appropriate to the context;
• make sufficient observations and measurements to reduce error and obtain reliable evidence;
• judge the level of uncertainty in observations and measurements;
• represent and communicate qualitative and quantitative data using diagrams, tables, charts, and graphs.

A Basic Data Section will

• O3a collect some evidence using a simple and safe procedure
• O3b collect appropriate evidence which is adequate for the activity
• O3c record the evidence

A Good Data Section will

• O4a collect sufficient systematic and accurate evidence and repeat or check when appropriate
• O4b record clearly and accurately the evidence collected

An Excellent Data Section will

• O5a use a procedure with precision and skill to obtain data
• O5b report the instrumental precision possible with the procedure

Assessment and Grades
I will use the codes above to let you know what skills you have demonstrated. Seeing these codes is a good thing! If any of the codes are missing from a given level, the data section does not yet meet the standards for that level. I will try to give you some guidance on reaching the next step; you are always free to try to move two levels at once, but this is clearly a more challenging undertaking. For the first marking period, I am happy to accept resubmitted reports with new data sections added as an addendum to the original.